The London-based mavericks are joined by the Architects Design Partnership, BBM Sustainable Design, Patel Taylor Architects, Design Engine Architects and Tim Ronalds Architects on the shortlist to revamp the 70ha Sedlescombe site.
The Pestalozzi International Village Trust, an educational charity set up in 1957, is searching for an architect to overhaul its existing estate, which lies in an area of outstanding natural beauty.
More than 43 practices submitted expressions of interest to the RIBA-organised competition, and trust chief executive, Derek Marshall, said he was impressed by the quality of the entrants.
He said: 'Pestalozzi International Village Trustees are delighted with the response to the competition and with the quality and engagement of the shortlisted submissions.'
The six shortlisted architects will now be asked to RIBA's headquarters at Portland Place for interviews.
The jury panel will be chaired by the Duke of Gloucester and a winner is expected to be announced at the beginning of April.